Python SortedList class derived from List

SortedList.py

# sorted list


class SortedList(list):
    def __init__(self, initial_list_values):
        super().__init__(sorted(initial_list_values))

    def append(self, new_value) -> None:
        for pos, value in enumerate(self):
            if new_value <= value:
                super().insert(pos, new_value)
                break
        else:
            super().append(new_value)

    def extend(self, new_list) -> None:
        for value in new_list:
            self.append(value)

    def insert(self, fake_index, new_value) -> None:
        self.append(new_value)

if __name__ == '__main__':
    s = SortedList([2, 5, -1, 8])
    print(s)
    s.append(-19)
    print(s)
    s.append(999)
    print(s)
    s.append(7)
    print(s)
    s.insert(3, 4)
    print(s)